JP2022539977A - Battery system, battery treatment method - Google Patents

Abstract

In the disclosed battery system, when the battery pack and the battery management device are connected and the battery pack and the charging device are not connected, state information of each battery module calculated by each of the plurality of battery modules, or , the state information of each battery module calculated by the battery management device is shared between each battery module and the battery management device. When the battery pack and the charging device are connected and the battery pack and the battery management device are not connected, the state information of each battery module calculated by each of the plurality of battery modules is stored in the respective battery modules and the charging device. share between [Selection drawing] Fig. 8

Description

The present invention relates to a battery system and a battery treatment method.

2. Description of the Related Art In recent years, electric vehicles that run on an electric motor and hybrid vehicles that have an internal combustion engine and an electric motor as power sources have become popular. 2. Description of the Related Art A secondary battery (hereinafter simply referred to as "battery") is installed in a vehicle that uses an electric motor for driving, such as an electric vehicle or a hybrid vehicle.

In order to monitor the state of the battery in a vehicle in which the battery is mounted, it is known to calculate state information such as a state of charge (SOC) (for example, Japanese Patent Application Laid-Open No. 2011-113759; See JP-A-2011-151983).

By the way, in many cases, the battery is configured to be detachable in a device such as a vehicle in which the battery is mounted. Therefore, the battery is used in various ways, such as operating a device in which the battery is mounted, removing the battery from the device and charging the battery with a charging device, or attaching the battery to another device after removing it from the device and operating it. There are various usage patterns such as cases. Considering such various usage patterns including battery replacement, conventionally, there is a problem that the battery charging/discharging control cannot be continued accurately.

For example, when a device is operated by attaching a battery charged at a charging station to the device, the conventional system described in the above-mentioned document calculates the SOC of the battery after it is attached to the device, and calculates the battery based on the calculated SOC. control the charging and discharging operation of However, since the state information of the battery before it is attached to the device, such as the charging history information at the charging station, is not taken into account, there is a possibility that the charge/discharge control after operating the device may not be appropriate. .

Therefore, there is a demand for a mechanism that can continue to accurately control charging and discharging of the battery in various usage patterns of the battery.

One aspect of the present invention is a battery pack including a plurality of rechargeable battery modules connected in series, and a battery pack provided in a device that is a load of the battery pack and capable of communicating with each of the plurality of battery modules. a battery management device; a first current sensor provided in the device for detecting a first current flowing through the battery pack when the battery pack and the battery management device are connected; and charging the battery pack. a charging device capable of communicating with each of the plurality of battery modules; a second current sensor that detects two currents, wherein each of the plurality of battery modules detects a voltage of each battery module, the battery pack and the battery management device are connected, and When the battery pack and the charging device are not connected, based on the voltage of each battery module and the first current, either one of the battery modules or the battery management device controls the charging of the corresponding battery module. state information is calculated, the calculated state information of each battery module is shared between each battery module and the battery management device, the battery pack and the charging device are connected, and the battery pack and the battery management device are connected to each other; When the device is not connected, each battery module calculates state information of the corresponding battery module based on the voltage of each battery module and the second current, and the calculated state of each battery module is calculated. Information is shared between each battery module and the charging device, each battery module having a first memory in which corresponding state information is stored and a corresponding state information when the corresponding state information is calculated by the battery management device. , receiving the state information from the battery management device and writing it to the first memory; and receiving the state information from the charging device and writing the corresponding state information to the first memory when the corresponding state information is calculated by the charging device. a first control unit that writes to a memory; the battery management device includes a second memory that stores state information of each battery module; and the state information of each battery module that is calculated and written to the second memory. or, when the state information of each battery module is calculated by the corresponding battery module, a second control unit that receives the state information from each battery module and writes the state information to the second memory. is.

Another aspect of the present invention is a battery management method for a battery pack including a plurality of rechargeable battery modules connected in series, wherein the battery pack is placed in a device that is the load of the battery pack. a battery management device provided and a charging device for charging the battery pack, wherein the method comprises connecting the battery pack and the battery management device, and connecting the battery pack and the charging device; When not connected, (a-1) the battery management device acquires a first current flowing through the battery pack from a first current sensor provided in the device; and (a-2) a step in which either one of the battery modules or the battery management device calculates state information of the corresponding battery module based on the voltage detected in each battery module and the obtained first current; (a-3) sharing state information of each battery module calculated by each of the plurality of battery modules or state information of each battery module calculated by the battery management device; when the battery pack and the charging device are connected and the battery pack and the battery management device are not connected, (b-1) the charging device causes a second current to flow through the battery pack, obtaining from a second current sensor in the charging device; and (b-2) each battery module calculating status information of the corresponding battery module based on the voltage of each battery module and the second current. and (b-3) sharing state information of each battery module calculated by each of the plurality of battery modules between each battery module and the charging device.

1 is a diagram showing a schematic configuration of a battery system of an embodiment when a battery pack is connected to a vehicle; FIG. 1 is a diagram showing a schematic configuration of a battery system of an embodiment when a battery pack is connected to a charging station; FIG. 3 is a functional block diagram of the battery system of the embodiment when the battery pack is connected to the electric vehicle; FIG. 4 is a functional block diagram of the battery system of the embodiment when the battery pack is connected to the charging station; FIG. 4 is a diagram showing a configuration example of a memory included in a cell management unit in the battery system of the embodiment; FIG. 4 is a sequence chart showing master BMU processing of the battery system of the embodiment; 4 is a sequence chart showing master CMU processing of the battery system of the embodiment; 4 is a sequence chart showing an example of handover of state information of battery modules in the battery system of the embodiment. 4 is a sequence chart showing an example of handover of state information of battery modules in the battery system of the embodiment. 4 is a flowchart showing SOC determination processing in the battery management device of the embodiment;

A battery system 1 according to an embodiment of the present invention will be described below. A battery system 1 of the present embodiment is a system for managing a battery pack mounted in a vehicle (an example of equipment), for example.
In the battery system 1 of the present embodiment, when a vehicle equipped with a battery pack is operated, when the battery pack is removed from the vehicle and charged at a charging station, or when the battery pack is removed from the vehicle and transferred to another vehicle. In consideration of various usage patterns such as the case where the battery pack is attached to the battery pack and operated, the battery module is configured to take over the state information of each of the plurality of battery modules included in the battery pack. For example, the battery module status information is configured to be handed over from the battery management unit in the vehicle to the battery module or from the battery module to the charging station.
In the description of this embodiment, the charging station is an example of the charging device of the present invention. The charging station of the present embodiment is a facility for charging a battery pack that has been removed from the vehicle, unlike a charging station that charges the battery pack through a charging port of the vehicle.

(1) Overall Configuration of Battery System First, the overall configuration of a battery system 1 of the present embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a diagram showing a schematic configuration of a battery system 1 of this embodiment when a battery pack 2 is connected to a vehicle. FIG. 2 is a diagram showing a schematic configuration of the battery system 1 of this embodiment when the battery pack 2 is connected to the charging station.

Referring to FIG. 1, when the battery pack 2 is mounted on the vehicle, the connector Cv of the vehicle and the connector Cb of the battery pack 2 are connected. In FIG. 1, the connectors Cv, Cb are shown schematically. The battery pack 2 is configured by, for example, connecting a plurality of battery modules 20-1 to 20-4 in series.
The number of battery modules included in the battery pack 2 is not limited to the example shown in FIG. 1, and can be set to a desired number. For convenience of explanation, an example in which a single battery pack 2 is mounted on the vehicle will be described, but the number of battery packs 2 mounted on the vehicle can be set to a desired number.
In the following description, when referring to matters common to each of the plurality of battery modules 20-1 to 20-4, they are collectively referred to as "battery module 20" as appropriate.

Each battery module 20 includes a plurality of stacked battery cells (battery cell group) and a cell management unit (CMU) connected to both ends of each battery cell. That is, as shown in FIG. 1, the plurality of battery modules 20-1 to 20-4 respectively include a plurality of battery cell groups 21-1 to 21-4 and a plurality of cell management units (CMUs). 22-1 to 22-4. As shown in FIG. 1, battery cell groups 21 of a plurality of battery modules 20-1 to 20-4 are connected in series. Each battery cell group may have a configuration in which a plurality of combinations of battery cells connected in parallel are connected in series (for example, an 8s4p type battery module or the like).

In the following description, when referring to matters common to each of the plurality of battery cell groups 21-1 to 21-4, the term "battery cell group 21" will be used as appropriate, and the plurality of cell management units 22-1 22-4 are collectively referred to as "cell management unit 22".
In the following description, the voltage across the battery cell groups 21-1 to 21-4 connected in series is equivalent to the voltage of the corresponding battery module, and the voltage across the plurality of battery modules connected in series is Equivalent to the corresponding battery pack voltage.

A cell management unit 22 includes electronic circuitry for controlling the corresponding battery module 20 . When the battery pack 2 is mounted on the vehicle, the cell management unit 22 is connected to a battery management unit (BMU) 3 of the vehicle. A battery system CAN (Controller Area Network) bus 101 is used for data communication between the cell management unit 22 and the battery management unit 3 .

When the battery pack 2 is mounted on the vehicle, a closed circuit is formed in which the battery cell groups 21-1 to 21-4 are connected in series. A vehicle-side load L1 and a current sensor 4 (an example of a first current sensor) provided on the vehicle for detecting current flowing through the closed circuit are connected to the closed circuit.
The load L1 is, for example, a power converter such as an inverter. The inverter converts the DC voltage of the battery pack 2 into AC voltage and supplies it to an AC motor (for example, a three-phase AC motor) used to drive the vehicle.
When the cell management unit 22 is connected to the battery management unit 3 of the vehicle, the battery pack 2 can be charged by charging the battery pack 2 with regenerated power from the AC motor when the vehicle decelerates. The battery pack 2 can be charged from the provided charging port through a household power supply or from a charging stand (for example, a quick charger) compatible with the CHAdeMO standard through a charger in the vehicle.

The battery management unit 3 is a control device for acquiring the current value detected by the current sensor 4, acquiring the voltage value of the battery module 20 from the battery module 20, and controlling charging and discharging of the battery module 20. The battery management unit 3 is connected to a current sensor 4 and a vehicle control unit (VCU) 5, which is a higher-level control device in the vehicle. A vehicle system CAN bus 102 is used for data communication between the battery management unit 3 and the vehicle control unit 5 .

The battery management unit 3 notifies the vehicle control unit 5 of state information such as the state of charge (SOC) of the battery pack 2 and an error code, for example. For example, upon receiving information on the SOC of the battery pack 2 from the battery management unit 3, the vehicle control unit 5 displays an SOC indicator corresponding to the SOC on the instrument panel of the vehicle. Upon receiving the error code from the battery management unit 3, the vehicle control unit 5 displays a warning indicator corresponding to the error code on the instrument panel of the vehicle.

Referring to FIG. 2, when the battery pack 2 is connected to the charging station, the connector Cs of the charging station and the connector Cb of the battery pack 2 are connected. In FIG. 2, the connectors Cs, Cb are shown schematically. When the battery pack 2 is mounted on the charging station, the cell management unit 22 is connected to the charging control unit 6 of the charging station. In this state, the cell management unit 22 and the charge control unit (CCU) 6 can communicate with each other via the CAN bus 103 .

When the battery pack 2 is connected to the charging station, a closed circuit is formed in which the battery cell groups 21-1 to 21-4 are connected in series. A current sensor 7 (an example of a second current sensor) provided at the charging station for detecting current flowing through the closed circuit is connected to the closed circuit.
The charging control unit 6 acquires the current value detected by the current sensor 7 , acquires the voltage value of the battery module 20 from the battery module 20 , and controls charging of the battery module 20 .

In CAN communication performed via CAN buses 101-103, at least one of cell management unit 22, battery management unit 3, and charging control unit 6 can be a transmitting node or a receiving node. A data frame transmitted from a transmitting node contains data and an ID for identifying the transmitting node. This ID is also used for communication arbitration. That is, when a plurality of transmitting nodes transmit frames to the bus at the same time, the priority of occupying the bus is determined according to the ID value of the transmitting node, and collision of frames from transmitting nodes with different IDs is avoided.
The transmission of the data frame by the transmitting node may be performed according to the transmission of the remote frame by the receiving node, or may be performed without using the remote frame.

(2) Configuration of Each Unit of Battery System Next, the configuration of each unit of the battery system 1 of the present embodiment will be described with reference to FIGS. 3 to 5. FIG. FIG. 3 is a functional block diagram of the battery system 1 of this embodiment when the battery pack 2 is connected to the vehicle. FIG. 4 is a functional block diagram of the battery system 1 of this embodiment when the battery pack 2 is connected to the charging station. FIG. 5 is a diagram showing a configuration example of a memory included in the cell management unit 22 of this embodiment.
In the following description, the state information of the battery module 20 is abbreviated as "state information" as appropriate.

(2-1) Cell Management Unit Referring to FIG. 3, the cell management unit 22 includes a controller 221 (an example of a first control section), a memory 222 (an example of a first memory), a cell monitoring unit 223, and a CAN. and a transceiver 224 .
The controller 221 includes a microcomputer, ROM (Read Only Memory), RAM (Random Access Memory), A/D (Analog to Digital) converter, and the like. In the controller 221, the functions required of the battery module 20 are realized by the microcomputer executing a predetermined program.

The functions realized by the controller 221 include at least the following contents.
(1-i) controlling the CAN transceiver 224 to receive data frames containing current values detected by the current sensor 4 or the current sensor 7 from the CAN bus 101 or 103;
(1-ii) Calculating the state information of the battery module 20 based on the voltage value of the battery module 20 and the current value acquired from the charging control unit 6 at preset timing.
(1-iii) controlling the CAN transceiver 224 so as to transmit the data frame containing the calculated state information of the battery module 20 to the CAN bus 103;
(1-iv) writing the calculated state information or the state information received by the CAN transceiver 224 to the memory 222;
(1-v) Control the CAN transceiver 224 so as to transmit a data frame containing the voltage value of the battery module 20 to the CAN bus 101 as necessary.

The memory 222 is a nonvolatile memory such as a flash memory, and stores a battery module code that identifies the battery module 20 and state information calculated by the controller 221 or state information obtained from the battery management unit 3 . The battery module code is written into memory 222 when battery module 20 is manufactured.
As illustrated in FIG. 5, the state information of the battery module 20 includes parameters of SOC (State of Charge), SOH (State of health), cycle count, and error code. For example, one sector is allocated for each parameter in memory 222 .

The timing of writing the SOC and SOH to the memory 222 is not particularly limited, but for example, they are written to the memory 222 every predetermined time (every three seconds, for example). The interval between the timings for calculating the SOC and SOH may be shorter than the interval between the timings for writing the SOC and SOH.
Here, considering the rewrite life of the memory 222, writing is preferably performed as follows.
For example, as shown in FIG. 5, one sector in the memory 222 to store the SOC is composed of 2K bytes (2048 bytes), and data is written in order for each 2-byte write area. At this time, only when the SOC calculated this time has changed by 0.5% or more from the SOC stored in the N-1th write area last time, the SOC calculated this time is stored in the Nth write area. Overwrite the SOC. If the SOC calculated this time does not change by 0.5% or more, the SOC calculated this time is not overwritten in the Nth write area.
Similarly, as shown in FIG. 5, one sector in the memory 222 for storing SOH is composed of 2K bytes (2048 bytes), and data is sequentially written in each 2-byte write area. At this time, only when the SOH calculated this time has changed by 0.1% or more from the SOH stored in the N-1th write area last time, the SOH calculated this time is stored in the Nth write area. Overwrite SOH. If the SOH calculated this time does not fluctuate by 0.1% or more, the SOH calculated this time is not overwritten in the Nth write area.
When the calculated SOC drops below 50% and when the SOC exceeds 95%, the cycle count is incremented and written to the corresponding sector of memory 222 . At this time, a value obtained by incrementing the cycle count recorded in the (N-1)th write area is written in the Nth write area.

In the case of the SOC with the highest rewrite frequency, the SOC recording function is as follows. In the example of the above memory configuration, for example, when the SOC is written to each write area about 1000 times (for example, after 3000 seconds), the writing of the sector assigned to the SOC ends. data is written. Assuming that the number of rewritable times of the memory 222 is 100,000 times, it has a recording function of 100,000 times×3000 seconds=about 10 years, and there is no practical problem. As described above, by writing the SOC only when the variation between the previous value and the current value is large, the recording function for a longer period is provided.

When an event occurs that satisfies a predefined error occurrence condition, an error code corresponding to the event is written to the sector corresponding to the error code in the memory 222 . The error occurrence conditions include, for example, a condition that the temperature detected by a temperature sensor (not shown) provided in the battery module 20 is higher than a predetermined threshold, a condition that the voltage value of the battery module 20 indicates an abnormal value, and the like. be.

Preferably, memory 222 stores attribute data unique to battery module 20 .
The attribute data includes manufacturer code, date of manufacture, serial code, battery type, and combination code. For example, when the battery pack 2 is composed of four battery modules 20, the memory 222 of each of the four battery modules 20 to which attribute data is assigned to each battery module 20 stores any one of the attribute data. data should be stored.

Preferably, the attribute data is referred to by the battery management unit 3 when the cell management unit 22 and the battery management unit 3 are initialized, and used for verification of the battery pack 2 . For example, as a combination code, a common code is assigned to a plurality of battery modules forming the same battery pack 2 . In that case, the battery management unit 3 transmits a predetermined error code to the vehicle control unit 5 when the combination codes assigned to all the battery modules in the battery pack 2 mounted on the vehicle are not the same. Thereby, the correct combination of battery modules in the battery pack 2 is maintained. In that case, since the usage history of each battery module in the battery pack 2 is the same, for example, the SOH of all the battery modules can be equally maintained.

The cell monitoring unit 223 detects the inter-terminal voltage of each battery cell in the battery cell group 21 and performs battery cell balancing. Battery cell balancing makes the voltage of each battery cell substantially the same when there is a difference in voltage between the battery cells of the battery cell group 21 connected in series (that is, the voltage of each battery cell is equalization). By performing battery cell balancing, the battery capacity of the battery module 20 can be maximized. Cell monitoring unit 223 is an example of a cell balancer.
The battery cell balancing method is not particularly limited, and may be passive balancing or active balancing.

CAN transceiver 224 is a communication interface unit that communicates according to the CAN protocol.
The CAN transceiver 224 transmits signals (for example, signals corresponding to data frames) from the controller 221 to the CAN buses 101 and 103, and also transmits signals transmitted from the battery management unit 3 and the charging control unit 6 to the CAN buses 101 and 103, respectively. 101, 103. A data frame sent from CAN transceiver 224 to CAN buses 101 and 103 includes an ID that identifies cell management unit 22, which is a transmission node.

(2-2) Battery Management Unit Referring to FIG. 3 again, the battery management unit 3 includes a controller 31 (an example of a second control section), a memory 32 (an example of a second memory) and a CAN transceiver 33. include.
The controller 31 includes a microcomputer, ROM, RAM, A/D converter and the like. In the controller 31, the functions required of the battery management unit 3 are realized by the microcomputer executing a predetermined program.

The functions realized by the controller 31 include at least the following contents.
(2-i) controlling the CAN transceiver 33 to receive a data frame containing the voltage value of the battery module 20 from the CAN bus 101;
(2-ii) Calculating the state information of the battery module 20 based on the voltage value of the battery module 20 and the current value detected by the current sensor 4 at preset timing.
(2-iii) Control the CAN transceiver 33 so as to transmit the data frame containing the calculated state information of the battery module 20 to the CAN buses 101 and 102.
(2-iv) Determining the SOC to be notified to the vehicle control unit 5 (see SOC determination processing described later)

The memory 32 is, for example, a non-volatile memory such as a flash memory. store information and The configuration of the memory 32 may be the same as the configuration shown in FIG.

In relation to (2-iv) above, the controller 31 performs initialization with each of the battery module 20 and the vehicle control unit 5, and the SOC obtained from the battery module 20 and the SOC recorded in the memory 32 are stored in the memory 32. The SOC to be notified to the vehicle control unit 5 is determined based on the result of comparison with the SOC of the battery module 20 that is stored. This determination method will be described later.

If there is a difference in the SOC or voltage calculated for the battery modules 20-1 to 20-4, the controller 31 causes the cell monitoring unit 223 of each battery module 20 to monitor the battery modules 20-1 to 20-4. Battery modules 20-1 to 20-4 may be controlled so that the SOC or voltage is substantially the same among them. For example, the controller 31 notifies each battery module 20 of the lowest voltage value among the voltages of the battery modules 20-1 to 20-4, and the cell monitoring unit 223 of each battery module 20 conforms to the notified voltage value. A process for discharging the battery cell group 21 is performed so as to
Controller 31 preferably notifies each battery module 20 of the substantially identical SOC data.

The CAN transceiver 33 is a communication interface unit that communicates according to the CAN protocol.
The CAN transceiver 33 is configured to transmit signals (eg, signals corresponding to data frames) from the controller 31 to the CAN buses 101 and 102 and to receive signals transmitted from the cell management unit 22 from the CAN bus 101. be done. A data frame sent from CAN transceiver 33 to CAN buses 101 and 102 includes an ID that identifies battery management unit 3, which is a transmission node.

(2-3) Charging Control Unit Referring to FIG. 4, the charging control unit 6 includes a controller 61, a memory 62, and a CAN transceiver 63.
The controller 61 includes a microcomputer, ROM, RAM, A/D converter and the like. In the controller 31, the functions required of the charging control unit 6 are realized by the microcomputer executing a predetermined program.

The functions realized by the controller 61 include at least the following contents.
(3-i) controlling the CAN transceiver 63 to receive data frames containing state information of the battery module 20 from the CAN bus 103;
(3-ii) controlling the CAN transceiver 63 so as to transmit a data frame containing the current value detected by the current sensor 7 to the CAN bus 103;
(3-iii) Control charging of the battery module 20
(3-iv) generating image data for displaying at least part of the state information (for example, SOC) acquired from the battery module 20 on the display device 65 of the charging station;

The memory 62 is a non-volatile memory such as a flash memory, and stores, for example, a battery module code obtained from the battery module 20 and status information obtained from the cell management unit 22 while the battery module 20 is being charged. The configuration of the memory 62 may be the same as the configuration shown in FIG.

The CAN transceiver 63 is a communication interface unit that communicates according to the CAN protocol.
CAN transceiver 63 is configured to transmit signals (eg, signals corresponding to data frames) from controller 61 to CAN bus 103 and to receive signals transmitted from cell management unit 22 from CAN bus 103 . . A data frame sent from CAN transceiver 63 to CAN bus 103 includes an ID that identifies charge control unit 6, which is a transmission node.

(3) Calculation method of SOC and SOH As described above, the cell management unit 22 calculates the state information of the battery module 20 based on the voltage value of the battery module 20 and the current value obtained from the charging control unit 6. , the battery management unit 3 calculates the state information of the battery module 20 based on the voltage value of the battery module 20 and the current value detected by the current sensor 4 . That is, SOC and SOH, for example, are calculated based on the voltage value of the battery module 20 and the current value flowing through the battery module 20 .
Although the method for calculating SOC and SOH is not limited here, a preferred method for calculating them will be described below. Although the case where the cell management unit 22 calculates the SOC and SOH will be described below, the same applies to the battery management unit 3 as well.

When the designed capacity of the battery module 20, that is, the initial full charge capacity (referred to as “initial capacity”) is FCC ₀ , and the full charge capacity in the lifetime of the battery module 20 is FCC (variable), the FCC is It decreases with the use of the battery module 20 and the passage of time. FCC degradation is primarily caused by two modes of degradation: cycle life and calendar life. The cycle life is the deterioration mode when the battery is repeatedly charged and discharged, and the calendar life is the deterioration mode when the battery is left unattended.
Here, in calculating the SOH, the cell management unit 22 refers to a lookup table for specifying deterioration coefficients for each of cycle life and calendar life. The cycle life lookup table is data indicating the relationship between the cycle count and the deterioration coefficient (degree of deterioration of capacity). The cycle life lookup table is data obtained from cycle counts and FCC measurements under given depth of discharge conditions.
The calendar life lookup table is data obtained from experimental results when the battery module 20 is adjusted to a predetermined SOC and left at a predetermined temperature, and indicates the relationship between time and deterioration coefficient (degree of deterioration of capacity). Data.
The cell management unit 22 sequentially updates the FCC (full charge capacity) based on these two deterioration factors. In other words, the FCC (full charge capacity) gradually decreases from FCC0 (initial capacity) during the lifetime of the battery module 20 . Further, the cell management unit 22 calculates SOH according to the formula SOH ₌ FCC/FCC0.
By providing the battery pack 2 with a temperature sensor and providing the lookup table for different temperatures, the accuracy of the calculated SOH can be further improved.

Furthermore, the cell management unit 22 calculates the current consumption capacity (CCC) due to charging and discharging based on the voltage value of the battery module 20 and the current value flowing through the battery module 20 . The SOC of the battery module 20 is calculated by the above FCC and CCC. That is, the SOC of battery module 20 is calculated according to the equation SOC=1-(CCC/FCC).

(4) Operation of Battery System Next, operation of the battery system 1 of the present embodiment will be described with reference to FIGS. 6 and 7. FIG.
In the battery system 1 of this embodiment, one of the master BMU process and the master CMU process is performed according to the usage state of the battery pack 2 .
Master BMU processing is processing when the battery pack 2 is connected to the battery management unit 3 . In the master BMU process, the battery management unit (BMU) 3 acts as a master, and the cell management units 22 of the battery modules 20 act as slaves to operate cooperatively, and state information of each battery module 20 is calculated and recorded. FIG. 6 is a sequence chart showing master BMU processing in the battery system 1 of this embodiment.
Master CMU processing is processing when the battery pack 2 and the charging control unit 6 of the charging station are connected and the battery pack 2 and the battery management unit 3 are not connected. In the master CMU process, the cell management unit (CMU) 22 of the battery module 20 acts as a master and the charging control unit 6 of the charging station acts as a slave, and cooperates to calculate and record the state information of each battery module 20 . FIG. 7 is a sequence chart showing master CMU processing in the battery system 1 of this embodiment.

For example, when the vehicle is running, the battery pack 2 is mounted on the vehicle and connected to the battery management unit 3, so master BMU processing is performed. Also, when the battery pack 2 is charged from a charging station via a charger (not shown) in the vehicle, the master BMU process is performed because the battery pack 2 and the battery management unit 3 are connected. The master BMU process is repeatedly performed, for example, every 3 seconds.
On the other hand, when the battery pack 2 is removed from the vehicle and connected to the charging control unit 6 of the charging station to charge the battery pack 2, since the battery pack 2 and the battery management unit 3 are not connected, the master CMU process is executed. done. The master CMU process is repeated every three seconds, for example.
Note that the execution timing interval between the master BMU processing and the master CMU processing may be shorter than the timing interval (for example, 3 seconds) between writing the SOC and SOH.

(4-1) Master BMU processing (Fig. 6)
As described above, in master BMU processing, the battery management unit 3 installed in the vehicle acts as a master, and the cell management unit 22 of the battery module 20 acts as a slave. SOC and SOH of are calculated.
Referring to FIG. 6, in the master BMU process, each process of steps S10 to S26 is repeatedly performed as a subroutine. In this subroutine, as described above, SOC and SOH are calculated every predetermined time (for example, every three seconds) and written to the memory 32 of the battery management unit 3 and the memory 222 of the cell management unit 22 .

That is, when the next write timing comes after a lapse of a predetermined time from the previous write timing (step S10: YES), the battery management unit 3 acquires the current value detected by the current sensor 4 provided in the vehicle (step S12). Further, the battery management unit 3 transmits a data request for voltage data of the battery module 20 to the cell management unit 22 (step S13). The cell management unit 22 transmits voltage data including the voltage value of the battery module 20 to the battery management unit 3 in response to the data request (step S14).

Next, the battery management unit 3 calculates the state information of the battery module 20 (step S16). More specifically, battery management unit 3 calculates SOC and SOH as state information of battery module 20 based on the current value and voltage value obtained in steps S12 and S14. The calculation method of SOC and SOH is as already explained. The cycle count as the state information of the battery module 20 is based on the calculated SOC under a predetermined condition (for example, the condition that the calculated SOC has decreased to 50% or less, or the condition that the SOC has exceeded 95%). is incremented when That is, in step S16, the SOC, SOH, and cycle count data are calculated as the state information of the battery module 20 .
Although not shown in the sequence chart of FIG. 6, when an event that satisfies a predefined error occurrence condition occurs in the battery module 20, the battery management unit 3 outputs an error code corresponding to the event. It is specified as the state information of the battery module 20 .

The battery management unit 3 transmits SOC, SOH, cycle count, and an error code according to the occurrence of an event as status information of the battery module 20 to the cell management unit 22 and the vehicle control unit 5 (step S18, S20), and write to the memory 32 (step S22). The cell management unit 22 writes the state information received in step S18 to the memory 222 (step S24). The vehicle control unit 5 performs processing for updating the display information of the vehicle based on the state information received in step S20 (step S26).

In step S26, upon receiving the SOC information of the battery module 20 from the battery management unit 3, the vehicle control unit 5 displays an SOC indicator corresponding to the SOC on the instrument panel of the vehicle. Further, upon receiving an error code from the battery management unit 3, the vehicle control unit 5 displays a warning indicator corresponding to the error code on the instrument panel of the vehicle.

As described above, in steps S22 and S24, data is sequentially written into each write area of the memory when a predetermined condition is satisfied. For example, in the case of SOC, only when the SOC calculated this time has changed by 0.5% or more from the SOC stored in the previous N-1th write area, Overwrite the SOC calculated this time. If the SOC calculated this time does not change by 0.5% or more, the SOC calculated this time is not overwritten in the Nth write area.
By performing the processing shown in FIG. 6, in the master BMU processing, the SOC, SOH, and cycle count of the battery module 20 are calculated at predetermined time intervals while the battery module 20 is being charged and discharged. Historical data is recorded in memory. When data has been written to all write areas of the sector in the memory assigned to each of SOC, SOH and cycle count, the data in the sector is erased and new data is written.

(4-2) Master CMU processing (Fig. 7)
As described above, in the master CMU processing, the cell management unit 22 of the battery module 20 serves as the master and the charging control unit 6 of the charging station serves as the slave and cooperates to operate the battery module 20 substantially in real time. Calculate SOC and SOH.
Referring to FIG. 7, in the master CMU process, each process of steps S32 to S46 is repeatedly performed as a subroutine from the start of charging (step S30) to the end of charging (step S48). In this subroutine, as described above, SOC and SOH are calculated every predetermined time (for example, every 3 seconds) and written to the memory 222 of the cell management unit 22 and the memory 62 of the charging control unit 6 .

That is, when the next write timing comes after a predetermined time has elapsed since the previous write timing (step S32: YES), the cell management unit 22 transmits a data request for current data to the charging control unit 6 of the charging station. (Step S33). In response to the data request, charging control unit 6 transmits current data including the current value detected by current sensor 7 of the charging station to cell management unit 22 (step S34). Furthermore, the cell management unit 22 acquires the voltage value of the battery module 20 (step S36).
Note that it is preferable to define a register and a message ID exclusively assigned only to data communication between the charging control unit 6 and the cell management unit 22, and to transmit the current data in step S34 via the message ID. . By predefining the conditions for activating the register, the cell management unit 22 can recognize that the communication partner has been switched from the battery management unit 3 to the charging control unit 6 .

The cell management unit 22 then calculates the state information of the battery module 20 (step S38). More specifically, cell management unit 22 calculates SOC and SOH as state information of battery module 20 based on the current value and voltage value obtained in steps S34 and S36. The calculation method of SOC and SOH is as already explained. The cycle count as status information of the battery module 20 is incremented when the calculated SOC satisfies a predetermined condition (for example, the condition that the calculated SOC exceeds 95%). That is, in step S38, the SOC, SOH, and cycle count data are calculated as the state information of the battery module 20 .
Although not shown in the sequence chart of FIG. 7, when an event that satisfies a predefined error occurrence condition occurs in the battery module 20, the cell management unit 22 outputs an error code corresponding to the event. It is specified as the state information of the battery module 20 .

The cell management unit 22 transmits SOC, SOH, cycle count, and an error code according to the occurrence of an event as status information of the battery module 20 to the charging station (step S40), and writes it to the memory 222 (step S42). The charging control unit 6 of the charging station writes the state information received in step S40 to the memory 62 (step S44).

As in the master BMU process, in steps S42 and S44 of the master CMU process, data is sequentially written into each write area of the memory when a predetermined condition is satisfied.
By performing the processing shown in FIG. 7, in the master CMU processing, the SOC, SOH, and cycle count of the battery module 20 are calculated at predetermined time intervals while the battery module 20 is being charged, and the respective histories are calculated. Data is recorded in memory. When data has been written to all write areas of the sector in the memory assigned to each of SOC, SOH and cycle count, the data in the sector is erased and new data is written.
The charging control unit 6 determines whether or not the charging end condition is satisfied, for example, the SOC exceeds a predetermined threshold value. If the charging end condition is not satisfied (step S46: NO), the process returns to step S33. It waits for a data request from the cell management unit 22 . If the charging termination condition is satisfied (step S46: YES), the charging of the battery module 20 is terminated (step S48).

(5) Battery module state information handover operation in battery system Whether state information is shared between the management unit 22 and the battery management unit 3 and between the cell management unit 22 and the charge control unit 6 will be described.

An operation of taking over the state information of the battery modules 20 in the battery system 1 will be described below with reference to FIGS. 8 to 10. FIG.
8 and 9 are sequence charts showing an example of handover of state information of the battery module 20 in the battery system 1 of this embodiment. FIG. 10 is a flowchart showing an example of SOC determination processing for determining the SOC to be notified to the vehicle control unit 5 by the battery management unit 3 when the power of the vehicle is turned on.

(5-1) First handover example of battery module state information (Fig. 8)
FIG. 8 is a sequence chart when switching between a state in which the battery pack 2 is charged and discharged in the vehicle and a state in which the battery pack 2 is charged at the charging station.
First, it is assumed that the battery pack 2 is being charged and discharged while being mounted on the vehicle (that is, the master BMU process of FIG. 6 is executed) (step S50). In the master BMU process of step S50, the state information of the battery modules 20 is sequentially recorded in the cell management unit 22 substantially in real time.

Next, it is assumed that the battery pack 2 is removed from the vehicle and then connected to a charging station to charge the battery pack 2 . The charging station is provided with detection means for physically or electrically detecting that the battery pack 2 has been connected to the charging station. When the detection means detects that each battery module 20 of the battery pack 2 is connected to the charging station (step S52), the charging control unit 6 of the charging station and the cell management unit 22 of the battery module 20 Communication by CAN is established and initialization is performed (step S54).

During initialization in step S54, the state information of the battery modules 20 recorded in the memory 222 of the cell management unit 22 is handed over to the charging control unit 6 of the charging station. More specifically, the cell management unit 22 transmits the state information of the battery modules 20 recorded in the memory 222 to the charging control unit 6, and the charging control unit 6 records the received state information in the memory 62. . That is, when the battery pack 2 is connected to the charging station, the state information of the battery module 20 is shared between the battery module 20 of the battery pack 2 and the charging control unit 6 of the charging station.
When the initialization is completed, the charging control unit 6 controls so that charging of the battery module 20 is started. At this time, the charging control unit 6 starts charging control based on the state information handed over from the battery module 20 . Since control is started considering the state information before the start of charging, accurate control can be performed.
While the battery module 20 is being charged, the master CMU process (see FIG. 7) is executed between the cell management unit 22 and the charge control unit 6 (step S56), substantially in real time. State information of the battery modules 20 is shared.

Next, it is assumed that after the charging of the battery pack 2 is completed, the battery pack 2 is mounted in the vehicle again and the power is turned on. After the power is turned on, CAN communication is established between the cell management unit 22 and the battery management unit 3 and between the battery management unit 3 and the vehicle control unit 5 . After that, initialization including at least steps S80 to S90 is executed.

First, the state information of the battery module 20 recorded in the memory 222 of the cell management unit 22 is handed over to the battery management unit 3 . More specifically, the cell management unit 22 transmits the battery module 20 status information recorded in the memory 222 to the battery management unit 3 , and the battery management unit 3 records the received status information in the memory 32 .

At this time, preferably, verification is performed as to whether or not the battery pack 2 mounted on the vehicle includes the correct combination of battery modules 20 . In this case, the cell management unit 22 transmits the combination ID included in its own attribute data to the battery management unit 3 together with the state information (step S80). If all the combination codes included in the attribute data transmitted from the battery modules 20 included in the battery pack 2 are the same, the combination of the battery modules 20 is correct (step S82: YES), so the data is received in step S80. The obtained state information is recorded in the memory 32 (step S86). That is, when the battery pack 2 is mounted in the vehicle, the state information of the battery module 20 is shared between the battery module 20 of the battery pack 2 and the battery management unit 3 in the vehicle.
On the other hand, if the combination codes included in the attribute data transmitted from each battery module 20 included in the battery pack 2 are not the same (step S82: NO), a predetermined error code is transmitted to the vehicle control unit 5 ( step S84). Upon receiving the error code, the vehicle control unit 5 performs processing to display a warning indicator corresponding to the error code on the instrument panel of the vehicle (step S92).

If battery pack 2 includes the correct combination of battery modules 20, battery management unit 3 executes SOC determination processing (step S88). The SOC determination process is a process for determining the SOC (referred to as "Vx") that is the basis of the SOC indicator displayed on the instrument panel of the vehicle after the battery pack 2 is mounted on the vehicle. Such processing is shown in the flow chart of FIG.

The SOC determination process will be described below with reference to FIG.
In the SOC determination process, first, the battery management unit 3 uses V1, which is the SOC last recorded in the memory 32 of the battery management unit (BMU) 3, and the latest SOC received from the cell management unit (CMU) 22 at the time of handover. A difference ΔSOC from a certain V2 is calculated (step S100). In the example of FIG. 8, the last SOC recorded in the memory 32 of the battery management unit (BMU) 3 is the last SOC written in the memory 32 in the master BMU process in step S50. The latest SOC received from the cell management unit (CMU) 22 at the time of handover is the latest SOC received in step S80.
Then, the battery management unit 3 determines Vx, which is the SOC that forms the basis of the SOC indicator, as follows. When |ΔSOC|, which is the absolute value of ΔSOC, is small, for example, when it is 5% or less, the battery management unit 3 sets Vx=V1 (that is, the last SOC recorded in the memory 32) (step S104). ). When |ΔSOC| is large, for example, when it is 10% or more, the battery management unit 3 sets Vx=V2 (that is, the latest SOC taken over) (step S108). When |ΔSOC| is larger than 5% and smaller than 10%, for example, the average value of V1 and V2 is set to Vx (step S106).
It should be noted that setting Vx to the average value of V1 and V2 in step S106 is merely an example, and any value between V1 and V2 may be used. In the above examples, V1, V2, and Vx are examples of the first charging rate, the second charging rate, and the third charging rate, respectively.

SOC (Vx) is determined as shown in FIG. This is to prevent discrepancies in the display of the SOC indicator displayed on the instrument panel of the vehicle. In the former case, the actual SOC of the battery module 20 hardly changes before and after the power is turned on. Large changes in SOC can occur. However, the battery management unit 3 cannot distinguish between the former case and the latter case. Therefore, if Vx=V1 (that is, the last SOC recorded in the memory 32), the SOC indicated by the SOC indicator remains low immediately after the power is turned on, even after the battery pack 2 is charged. contrary to people's expectations. Also, if Vx=V2 (that is, the latest SOC taken over), the SOC displayed on the SOC indicator will fluctuate immediately after the power is turned on, even if the power is simply turned on again. will cause discomfort.
Therefore, as shown in FIG. 10, it is preferable to determine Vx according to the absolute value of the difference between V1 and V2, thereby avoiding inconsistencies in the display of the SOC indicator. In this Vx determination method, an error may occur between the actual SOC of the battery module 20 and the SOC displayed on the SOC indicator. However, the SOC indicator displayed on the instrument panel of the vehicle has low display resolution. Therefore, the error does not pose a problem. For example, the SOC indicator is represented by several scales from low to full charge, and its resolution is often lower than the above error.

Referring to FIG. 8 again, after the initialization is completed, the charging and discharging of the battery pack 2 is started along with the operation of the vehicle. At this time, the battery management unit 3 starts charge/discharge control based on the state information handed over from the battery module 20 . Since control is started in consideration of state information before the start of charging/discharging, accurate control can be performed. When charging/discharging of the battery pack 2 is started, master BMU processing (see FIG. 6) is executed among the cell management unit 22, the battery management unit 3, and the vehicle control unit 5 (step S94).

(5-2) Second handover example of battery module status information (Fig. 9)
FIG. 9 is a sequence chart when the battery pack 2 mounted on the vehicle is replaced.
First, it is assumed that the battery pack including the battery module 20A is mounted in the vehicle and is being charged and discharged (that is, the master BMU process of FIG. 6 is executed) (step S70). In the master BMU process of step S70, the state information of the battery module 20A is sequentially recorded in the cell management unit 22 substantially in real time.

Next, assume that the battery pack of the vehicle is to be replaced. That is, it is assumed that the battery pack including the battery module 20B is mounted in the vehicle and the power is turned on instead of the battery pack including the battery module 20A.
In this case, the flow of the sequence chart of steps S80 to S94 is the same as in FIG. That is, the state information recorded in the battery module 20B is handed over to the battery management unit 3 of the vehicle during initialization. When the battery pack including the battery module 20B is mounted on the vehicle, the state information of the battery module 20B is shared between the battery module 20B of the battery pack and the battery management unit 3 inside the vehicle. Then, the battery management unit 3 starts charge/discharge control of the battery module 20B based on the handed-over state information of the battery module 20B. Therefore, the charging/discharging control of the battery pack 2 in the vehicle is continuously performed, and therefore the charging/discharging control can be appropriately performed.
In the case of FIG. 9 as well, since the SOC determination process is executed in step S88, even if there is a discrepancy between the last recorded SOC of battery module 20A and the latest SOC taken over from battery module 20B, , the display of the SOC indicator can be such that the driver does not feel uncomfortable.

As described above, in the battery system 1 of the present embodiment, when the battery pack 2 and the battery management unit 3 are connected and the battery pack 2 and the charging control unit 6 of the charging station are not connected, each battery State information of the module 20 is shared between each battery module 20 and the battery management unit 3 . When the battery pack 2 and the charging control unit 6 of the charging station are connected and the battery pack 2 and the battery management unit 3 are not connected, the state information of each battery module 20 is sent to each battery module 20 and the charging control unit. Share between 6. For example, when the battery pack 2 and the battery management unit 3 are connected, the state information of the battery module 20 is inherited by the battery management unit 3, and when the battery pack 2 and the charging station are connected, the state information is transferred to the battery module 20. is taken over by the charging control unit 6 of the charging station. Therefore, when the battery pack 2 mounted on the vehicle is replaced, or when the battery pack 2 is removed from the vehicle and charged at a charging station, etc., the state information of each battery module 20 that has been taken over is taken into account. Since charging/discharging control for the battery module 20 at the charging station and charging control for the battery module 20 at the charging station can be started, these controls can be optimized.

For example, in the present embodiment, the cell management unit 22 of the battery module 20 stores SOC and SOH history information and error codes as status information. By handing over this information to the vehicle side or the charging station side, the battery management unit 3 and/or the charging control unit 6 can start charging/discharging control or discharging control in consideration of the history information and error code. . By inheriting history information of SOC and SOH and error codes, more accurate charge/discharge control can be performed.

In the battery system 1 of the present embodiment, the state information of the battery module 20 to be handed over is limited to the SOC, SOH, cycle count, and error code parameters, so that the memory capacity of each unit can be made relatively small. can.
On the other hand, the state information to be handed over is not limited to each parameter of SOC, SOH, cycle count, and error code.

In the battery system 1 of the present embodiment, sensors for detecting current values flowing through the battery modules 20 necessary for calculating accurate state information for the battery modules 20 are provided on the vehicle side and the charging station side. In other words, battery module 20 does not include a current sensor. Therefore, the battery module 20 can be relatively inexpensive while maintaining accurate state information.

In the above-described embodiment, in the master BMU process of FIG. 6, the battery management unit 3 installed in the vehicle acts as a master, and the cell management unit 22 of the battery module 20 acts as a slave. Although the case of calculating the SOH has been described, the present invention is not limited to this. The cell management unit 22 of the battery module 20 may act as a master, and the battery management unit 3 may act as a slave to operate cooperatively. In that case, the cell management unit 22 acquires the current value detected by the current sensor 4 from the battery management unit 3 . Then, cell management unit 22 calculates the SOC and SOH of battery module 20 based on the voltage value of battery module 20 and the current value obtained from battery management unit 3 .

In the above-described embodiment, in the master CMU process of FIG. 7, the cell management unit 22 of the battery module 20 acts as a master, and the charging control unit 6 of the charging station acts as a slave. Although the case of calculating is described, it is not limited to this. The charging control unit 6 of the charging station may act as a master, and the cell management unit 22 of the battery module 20 may act as a slave to cooperate. In that case, the charge control unit 6 acquires the voltage value of the battery module 20 from the cell management unit 22 . Then, charging control unit 6 calculates the SOC and SOH of battery module 20 based on the voltage value acquired from cell management unit 22 and the current value detected by current sensor 7 .

All exemplifications and conditional expressions set forth in this specification are intended for instructional purposes to assist the reader in understanding the invention and its concepts which contribute to furthering the art of the inventors. Such specific set forth examples and conditions should be construed without limitation, and such example configurations in the specification do not relate to presenting the merits of the present invention. Although embodiments of the invention have been described in detail, it should be understood that various changes, substitutions, and substitutions can be made without departing from the spirit and scope of the invention.

1 Battery system 2 Battery pack 20-1 to 20-4 Battery module 21-1 to 21-4 Battery cell group 22-1 to 22-4 Cell management unit (CMU)
221 controller 222 memory 223 cell monitoring unit 224 CAN transceiver 3 battery management unit (BMU)
31 controller 32 memory 33 CAN transceiver 4, 7 current sensor 7
5...Vehicle control unit (VCU)
6... Charging control unit (CCU)
DESCRIPTION OF SYMBOLS 61... Controller 62... Memory 63... CAN transceiver 65... Display device 101... Battery system CAN bus 102... Vehicle system CAN bus Cb, Cv, Cs... Connector

Claims (9)

a battery pack including a plurality of rechargeable battery modules connected in series;
a battery management device provided in a device that is a load of the battery pack and capable of communicating with each of the plurality of battery modules;
a first current sensor provided in the device for detecting a first current flowing through the battery pack when the battery pack and the battery management device are connected;
a charging device for charging the battery pack, the charging device being communicable with each of the plurality of battery modules;
a second current sensor provided in the charging device for detecting a second current flowing through the battery pack when the battery pack and the charging device are connected;
A battery system comprising
each of the plurality of battery modules detects a voltage of each battery module;
When the battery pack and the battery management device are connected and the battery pack and the charging device are not connected, the voltage of each battery module or the battery is calculated based on the voltage of each battery module and the first current. one of the management devices calculates state information of the corresponding battery module, and shares the calculated state information of each battery module between each battery module and the battery management device;
When the battery pack and the charging device are connected and the battery pack and the battery management device are not connected, each battery module responds based on the voltage of each battery module and the second current. calculating the state information of each battery module, and sharing the calculated state information of each battery module between each battery module and the charging device;
Each battery module
a first memory in which corresponding state information is stored;
receiving the state information from the battery management device and writing it to the first memory when the corresponding state information is calculated by the battery management device; and when the corresponding state information is calculated by the charging device. comprises a first control unit that receives the state information from the charging device and writes it to the first memory;
The battery management device
a second memory storing state information of each battery module;
state information of each battery module is calculated and written to the second memory, or if the state information of each battery module is calculated by the corresponding battery module, the state information is received from each battery module and the a second control unit that writes to the second memory,
battery system. the state information of each battery module includes information of the state of charge (SOC) of each battery module;
The second control unit of the battery management device uses a first charging rate, which is the charging rate of each battery module stored in the second memory, and a charging rate of each battery module to be newly written in the second memory. calculating an absolute value of a difference from a certain second charging rate, and if the absolute value is equal to or less than a predetermined first threshold, notifying the first charging rate to a higher-level device; If the second charging rate is larger than the threshold, the second charging rate is notified to the higher-level device, and if the absolute value is larger than the first threshold and smaller than the second threshold, the charging rate is the second charging rate. Notifying the host device of a third charging rate that is between the first charging rate and the second charging rate;
The battery system according to claim 1. the state information of each battery module includes information of the state of charge (SOC) of each battery module;
Each battery module includes a plurality of battery cells connected in series and a cell balancer, and the cell balancer adjusts the voltage between the plurality of battery cells of each battery module when there is a difference in voltage between the plurality of battery cells. operates so that the voltages are substantially the same between
When there is a difference in the charging rate calculated for the plurality of battery modules, the second control unit of the battery management device adjusts the charging rate among the plurality of battery modules by the cell balancer of each battery module. controlling the plurality of battery modules to be substantially the same, and notifying each battery module of information on the substantially the same charging rate;
The battery system according to claim 1 or 2. The state information of each battery module includes at least state-of-charge (SOC) and state-of-health (SOH) information;
The battery system according to any one of claims 1 to 3. A battery management method for a battery pack including a plurality of rechargeable battery modules connected in series, comprising:
The battery pack is connectable to a battery management device provided in a device that is a load of the battery pack and a charging device for charging the battery pack,
In the method, when the battery pack and the battery management device are connected and the battery pack and the charging device are not connected,
(a-1) a step in which the battery management device acquires a first current flowing through the battery pack from a first current sensor provided in the device;
(a-2) Either one of the battery modules or the battery management device provides state information of the corresponding battery module based on the voltage detected by each battery module and the obtained first current. a calculating step;
(a-3) sharing state information of each battery module calculated by each of the plurality of battery modules or state information of each battery module calculated by the battery management device;
including
In the method, when the battery pack and the charging device are connected and the battery pack and the battery management device are not connected,
(b-1) the charging device acquiring a second current flowing through the battery pack from a second current sensor in the charging device;
(b-2) each battery module calculating state information of the corresponding battery module based on the voltage of each battery module and the second current;
(b-3) sharing state information of each battery module calculated by each of the plurality of battery modules between each battery module and the charging device;
including battery management methods. if the state information is calculated by the battery management device, each battery module receives corresponding state information from the battery management device and writes it to a first memory of each battery module;
each battery module receiving corresponding state information from the charging device and writing it to the corresponding first memory, when the state information is calculated by the charging device;
When the battery management device calculates state information of each battery module and writes it to the second memory of the battery management device, or when the state information of each battery module is calculated by the corresponding battery module, each battery module receiving the state information from and writing it to the second memory;
6. The battery management method of claim 5, comprising: the state information of each battery module includes information of the state of charge (SOC) of each battery module;
The method includes:
A first charging rate, which is the charging rate of each battery module stored in the second memory, and a second charging rate, which is the charging rate of each battery module to be newly written in the second memory. calculating the absolute value of the difference between
If the absolute value is equal to or less than a predetermined first threshold, the host device is notified of the first charging rate, and if the absolute value is equal to or greater than a second threshold larger than the first threshold, the second a step of notifying the higher-level device of the charging rate;
If the absolute value is greater than the first threshold and less than the second threshold, the host device is notified of a third charging rate that is between the first charging rate and the second charging rate. and
7. The battery management method of claim 6, comprising: the state information of each battery module includes information of the state of charge (SOC) of each battery module;
Each battery module includes a plurality of battery cells connected in series and a cell balancer, and the cell balancer adjusts the voltage between the plurality of battery cells of each battery module when there is a difference in voltage between the plurality of battery cells. operates so that the voltages are substantially the same between
The method includes:
When there is a difference in the charging rate calculated for the plurality of battery modules, the battery management device determines that the charging rate is substantially the same among the plurality of battery modules by the cell balancer of each battery module. controlling the plurality of battery modules such that
the battery management device notifying each battery module of the substantially identical charging rate information;
The battery management method according to claim 6 or 7, comprising: The state information of each battery module includes at least state-of-charge (SOC) and state-of-health (SOH) information;
The battery management method according to any one of claims 5 to 8.

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